Python（七）Socket编程、IO多路复用、SocketServer

本章内容：

Socket

IO多路复用（select）

SocketServer 模块（ThreadingTCPServer源码剖析）

Socket

socket通常也称作"套接字"，用于描述IP地址和端口，是一个通信链的句柄，应用程序通常通过"套接字"向网络发出请求或者应答网络请求。

class BaseRequestHandler:

"""Base class for request handler classes.

This class is instantiated for each request to be handled.  The
constructor sets the instance variables request, client_address
and server, and then calls the handle() method.  To implement a
specific service, all you need to do is to derive a class which
defines a handle() method.

The handle() method can find the request as self.request, the
client address as self.client_address, and the server (in case it
needs access to per-server information) as self.server.  Since a
separate instance is created for each request, the handle() method
can define arbitrary other instance variariables.

"""

def __init__(self, request, client_address, server):
self.request = request
self.client_address = client_address
self.server = server
self.setup()
try:
self.handle()
finally:
self.finish()

def setup(self):
pass

def handle(self):
pass

def finish(self):
pass

SocketServer.BaseRequestHandler
SocketServer的ThreadingTCPServer之所以可以同时处理请求得益于 select 和 Threading 两个东西，其实本质上就是在服务器端为每一个客户端创建一个线程，当前线程用来处理对应客户端的请求，所以，可以支持同时n个客户端链接（长连接）。

ForkingTCPServer

ForkingTCPServer和ThreadingTCPServer的使用和执行流程基本一致，只不过在内部分别为请求者建立 “线程” 和 “进程”。

基本使用：

#!/usr/bin/env python
# -*- coding:utf-8 -*-
import SocketServer

class MyServer(SocketServer.BaseRequestHandler):

def handle(self):
pass

if __name__ == '__main__':
server = SocketServer.ForkingTCPServer(('127.0.0.1',8009),MyServer)
server.serve_forever()